Outside pipe cutter



Patented Oct. 11, 1938 lPATilSu" OFFICE `.OUTSIDE PIPE `oU'r'rEIt 7 ."Dempson H. Reed, Houston, Tex. Application May 24, 1935, Serial No. 23,192

l 216 Claims.

`The invention relates .to .an outside pipe cutter of the type which is to be lowered into a well 4bore to telescopeovera piece vof pipe which is to be A'out and removed from the Well.

With the present :type oli outside `pipe cutter i it will :be understood that the well .bore is usually ,full of mud, sand', and other foreign materials so that the cutting operation usually has to be ,performed in 'a ,body ,of liquid and in many instances the tool Yand the 4 pipe being cut are rnot in a vertical position and the pipe may not be centered in .the tool so Ithat it is the exception rather than .the rule to have the parts in correct 4alignment and in perfect running `order so that ,a1-1 of the cutters will uniformly engage the pipe being cut. l

It is not :unusual rto have the cutter blades gouge -or dig into the pipe because of the `posistion of the tool relative to the pipe or because of the nature or condition ofthe pipe Ybeing cut and as la result of vother unavoidable circumstances. It is therefore one 4o f the objects of the Vinvention to `provide al -pipe cutter wherein the cutters will be Aforced to perform the cutting Aoperation by a .differential pressure which -is determined by the ,resistance which -is encountered bythe cutters. I

.Another object "of the invention is to provide a pipe cutter wherein a drive unit toxadvance the cutters is advanced in direct -proportion to `the amount of rotation so -long as the resistance to .the advancement of the ,cutter ,does not ex- ,ceed `a predetermined amount, andv to -provide `an arrangement whereinino further advancement 4of the cutters will be accomplished until the resistance lto advancement ldecreases below the predetermined value.

Another object .of the invention is :to `provide two ,friction drives to eiiect ,'advancernentof the cutters which are so arranged thatV only the `difierential pressure between the -two isavailable-to cause the advancement of the cutters.

Another object of the invention is `to :provide a 'rotatable set of cutters whose 4advancement is effected `by the relative rotation of a driving unit.

Still another object ofthe invention Alisto .pro- -vide a :driving Ipunit for pipe cutters y.wherein a 'slip vjoint connection `is Aprovided so that only a predetermined driving pressure can b e vapplied to -the cutters.

- Itis also an vobject of-the inventionto provide `azgripping device for .a .flush joint pipe in Vorder Tto actuate an voutsidepipe cutter. y

AOther and vfurther objects .of the invention will be ,readily apparent when the following description is ,considered in connection with the a ccornpanying `drawing wherein: u

Fig. lis a central, vertical, sectional View .of a pipe `cutter -embodying the invention and illus- 5 trating the arrangement .of the parts when a'cut has been partially completed.

Fig. 2 is a sectionalrview taken on the line 2 2 ^,of Fig. land looking downwardly.

Fig. 3 is a side elevation with certain vparts l0 broken away in `order vto illustrate the arrangement of the ,pipe .engaging ,dogs vby which the ,tool is anchored with respect .to the pipe being cut.

Fig. 4 is a sectional, vertical, central View of a modified form .of pipe engaging apparatus to 1 5v be employed when a'flush joint pipe is being cut.

The fish or pipe being cut is illustrated generally in Fig. l as `the ,pipe 2, and the usual form of such .pipeis ,provided with `couplings 3. This pipe 4for some reason or other may be junked M20 or stuck in ,a well bore and is to be severed so that it lmay :be removed.

The cutting tool lis illustrated lgenerally at 4 and may have any desired type of milling tool or cutter attached to the lower end 5 thereof. 25 The upper end of the .tool will be connected .to a string of pipe l which is known as .the operating string and i's .used to ,impart rotation to the `tool and vparticularly to the Itool housing v8. This .housing is preferably located 30 between the couplings 9 and vIl) so that an .enlarged chamber :Il -is formed by the housing. The lower .part of .this chamber is ,provided .with a v lateral opening i4 in whichthe cutter I5 is positioned. The cutter, however, is pivoted on 35 a Isupporting rib vI'I. rIhis rib may be fastened Ato ,the 4housing k8 by screws [8. This rib vIl is kslotted at 20 to provide acutter recess and the Ytransverse ypin 42| passes throughthe sides of the rib and supports .the cutter I5 in the :position `4.0 seen in Fig. 1 so that it may oscillate toward and away from the pipe 2.

In the form of. the .invention shown in Fig. 1 there rare three cutters Vl5 and, of course, three corresponding ribs ,|1. Intermediate these ribs 45 lIl .are the Ydrive wedges `or ngers 25 which are arranged .for longitudinal movement yrelative to the 4housing .8 as .will Abe .later described. These ngers 25 are preferably formed integral .with asupporting .ring ,26. The top of :the space between the ngers 2 5 is indicated at .21.

Theedges ,or sides .of these -fingers 2,5 are peculiarly ,formed 1,with a Alongitudinal .outstanding shoulder 2B which constitutes ,a wedge for causing advancement vof the cutters'. This shoulder 55 extends out from the normal face 29 of the edge of the finger 25 but is gradually tapered so that it becomes thinner and terminates in a rather sharp lower edge 3I.

Formed in the face 29 directly in front of the wedge 28 is a control slot 32 which is arranged to receive a lug 33 which is formed on the side of the cutter I on the outermost portion of the ear 35. This ear 35 has a beveled upper face 36 which is arranged to be abutted by the wedge 28 to force the cutter to pivot inwardly. The lug 33 travels in the slot 32, however, and prevents the cutter from advancing further than it is driven inwardly by the wedge 28. This prevents the cutter going into the pipe more than a predetermined amount so that the cutters will not take too large a bite into the metal and become broken. The particular conguration of the slot 32 should be noted because when :lt reaches the top of the wedge 28 it is deflected outwardly again so'as to cause the cutters to move back into the recess I4 so as to withdraw the cutters from engagement with the pipe. Both edges of each nger 25 are formed with the wedge 28 and slot 32 so that the cutter is conned in its proper position and supported at each side.

'Ihe under face 38 of the cutter is arranged to abut the beveled face 39 which is also formed on the edge 29 of the ngers 25. This engagement prevents the cutter from dropping inwardly while the tool is being lowered into position and only permits it to be advanced inwardly after the face 39 has moved downwardly away from the face 38 upon downward movement of the ngers 25.

A protective shoulder 4I) is carried by the housing 8 and positioned directly above the recess I4 so that the cutter cannot be injured as it is being lowered into or raised from the well bore. It will be understood that this shoulder 46 is positioned directly between the fingers 25 so that they can slide longitudinally on each side of this lug and the cutters I5.

In order to effect longitudinal movement of the wedge 28 to cause advancement of the cutter the fingers 25 and the head 26 are caused to move longitudinally of the housing 8 by means of the threaded friction drive 45. It will be noted that the threads 46 are of the acme square shoulder type so that considerable force can be exerted thereby. These threads 46 are arranged to engage corresponding threads 41 which are carried by the coupling 48 which is part of the housing 8. The friction drive 45 is a part of the entire drive unit 50 which is made up of the ngers 25 and the head 26 which are connected to a sleeve5I by means of the interlocking ring 52. This arrangement forms a shoulder to receive the anti-friction bearing 53 so that the head 26 and ngers 25 may rotate with respect to the sleeve 5I.

The sleeve 5I continues above the threads 46 and is provided with a plurality of slots 54 which receive the pins 55 carried by the slip joint head 55. In this manner the sleeve 5I may have relative longitudinal movement with respect to the slip joint head 56 but may not rotate relative thereto. Y

The slip joint head 56 is arranged with a friction surface 51 which is adapted to engage a similar and corresponding friction surface 58 which is carried by the ring 59. This ring 59 is fastened to a bushing 60 which carries a plurality of dogs 6I which are arranged to engage under the "coupling 3. AThe springs 63 are Vpositioned in the bushing 66 behind the dogs 6I to cause them to extend forwardly and click underneath the coupling 3 so that they will always be pressed into position. A cap 64 may be positioned over the dogs in order to protect them against injury. v

An antifriction bearing 65 is Vpositioned beneath the bushing 6I) and directly above the shoulder 66 which is formed on the inside of the housing 8. A compression spring is arranged between the slip joint head 56 and the coupling 58 in order to apply the desired upward pressure to the slip joint head 56. An antifriction bearing 12 may be provided between the spring and the slip joint head.

When a cut is to be made the parts are assembled as shown and lowered into the well until the dogs 6I click beneath a coupling such as 3 which is most closely adjacent the elevation where the cut is to be performed. In many instances the cutting tool is rotated by the string of pipe 1 as it is lowered into the well and telescopes over as much pipe which is to be recovered as possible. Different sized pipe and the conditions encountered in the well determine the maximum amount of pipe which can be cut and removed satisfactorily.

When the dogs 6I have clicked under the coupling 3 the entire tool is raised until the dogs are engaged firmly underneath the lower end of the coupling as seen in Fig. l. The desired strain or pull is then exerted on the pipe 1 so as to insure the desired frictional contact between -the dogs 6I and the collar 3, and to also insure that the entire tool will remain at the desired elevation so that an accurate cut may be made.

The next operation is to begin rotation of the string of pipe 1 and consequently the rotation of the housing 8 andthe cutters I5. It will be understood, however, that the bushing 6I) remains stationary because of the engagement of the dogs 6 I with the coupling 3. The thrust due to the strain on the operating pipe 1 is transferred to the bushing 60 through the antifriction bearing 65 which is resting on the shoulder 66. In this manner the ring 59 is, of course, fixed to the bushing 60 and remains stationary therewith.

The spring 10 exerts an upward pressure on the bearing 12 so that the slip joint head 56 is pressed upwardly against the ring 59 so that there is a frictional contact or drive between the faces 51 and 58 which constitutes the slip joint connection. Due to this friction between the faces 51 and 58 the slip joint head 56 will have a tendency to remain stationary with the dogs 6I. The pins 55 compel the sleeve 5I to remain stationary. The fingers 25- while connected to the sleeve 5I insofar as longitudinal movement is concerned, are free to rotate with the housing 8 and the cutters I5 because of the fact that they are straddling the ribs I1.

With the housing 8 caused to rotate by the string of pipe 1 and the sleeve 5I caused to remain stationary because of the dogs 6I, it seems obvious that there will be relative rotation be- Y tween the threads 46 and 41 so that the sleeve 5I will be caused to move downwardly with the slot 54 sliding on the pins 55 and fingers 25 moving downwardly with respect to the ribs I1 and the cutter I5. This downward movement of the ngers 25 causes the wedge 28 to move downwardly relative to the ears 36 so -that the thicker portion of the wedge gradually moves in behind the ear and causes-fthel cutter; to move forward on the pin. The initial downward movement of thefngers y25- moves the face 39 away from. the face 38 so that the cutters are unlocked. The 1ugs33 travel in the slot 32 and prevent the cutter from dropping downwardly vor' traveling faster than theyare forced forwardly by the wedge f 28.

It seems obvious that so longr as the cutters l do not encounter any unexpected Yresistance that the dogs 6| will remain stationary and the friction faces 51 and 58 will beheld together with a sufficient .pressure-because of the spring .toi hold. the sleeve 5|;against. rotation. Thus the threads 46 will becaused .to travel down- `war-dly relativetothe threads 41 andthethousing 8 and the cutters will be-advanced forward'- ly in direct proportion to the amount of rota- -tion of the housing 8 which rate Vof advancement depends and 41.

The particular novelty of the present invention resides in the arrangement of the-slip joint connectio-n between the faces. 51 and 58 when'considered in combination with the threads 46 and 41. As previously pointed out a great many cutters in tools of this type have beenbroken becauseof the fact that the tool is .compelled to operate in a bodyl of slush and grit with its Vparticular position unknown to the operator. If the cutter gouge-d into the pipe the operator was not aware of the fact andthe cutterwould be broken which necessitated the removal of the tool and replacement or" the cutter. rWhere the hole lis verydeep this operationmight require half a day or more, with the possibility of losing the fish. These twowfrictional surfaces, which for the purpose ofdescription may be described as the slip joint drive between the faces 51 and 58, and frictional vconnection between the threads 46 and 41.-, will be opposed to each other in compelling advancement of the cutters,

The provisionof these two 'friction surfaces is designatedas aA differential drive for the cutters because so long as the cutters are rtaking a normal bite into the pipe they will be caused to advance in direct-proportion to the amount of rotation of the housing 8.Y If, however, dic-ul-t cutting is encountered or the tooly is off-center so that some one cutter is compelled to carry more than its share of the load, it is then desirable to retard the advancement of the cutters, while upon the pitch of the threads 46 continuing their rotation, until the area causing the difficulty has been negotiated.

It seems obvious -that the slip joint friction drivey isthecontrolling factor of the advancement of the cutters, whereas the friction drive connection controls the amount of advancement.

When the cutters are pressed against the pipe there will be, of course, a resistance to downward movement bythe wedge 28.4 This resistance is transmitted to the sleeveV 5| in the form of a resistance against downward movement; that is, relative rotationbetween the housing 8 and thesleeve 5|. The friction necessary to compel this downward movement is transmitted from the threadsl 41 to the threads 46 and consti-tutes a friction connection. 'I'hereaction of this connection, however, `is transmi-tted from the sleeve 5| to the pins .551 andd-irectly to the slip joint friction-drivebetween-` the faces 51 and 58.. The; frictionitself exertedon these faces is a direct force which results from the amount of resistance to.l advancement encountered by the cutters.. v

f The spring, 'l0-.maybe adjusted by using. any

desired Strength of spring, o'r' shim's 12 may be positioned under. the lower end rof the spring where it abuts against the coupling 48 in any desired amount. The pressure which the spring will exert on the slip joint head 56, and accordingly the thrust which can be transmitted by the, slip joint friction connection, canin this manner becontrolled or varied as' desired. Various sized tools will have various strength springs and the desired adjustment may in this manner be obtained.

It seems' obvious that two friction differential surfaces are provided to withstand the'resistanceto advancement encountered Aby the cutters. The direct thrust will be from-the cutters to the slip joint connection. So long as the friction between the faces 51 and 58 is greater than the resistance encountered by the cutters the slip joint head 56 will remain stationary so that the threaded connection will cause advancement of the sleeve 5| and the cutting will proceed in a uniform manner. If one of the cutters. should gouge the pipe, a pit or pocket be encountered, or for any other reason. a shock is imparted to'one of the cutters so that it cannot rotate, the force of `thisgshock is transmitted to the friction faces 51 and 58, and if the shock is greater than the amount which can be resiste-d because of the setting of the spring 10, then the slip joint head 56 will rotate relative to the ring 59 landthis joint will slip.

As soon as the head 56 begins to rotate the sleeve 5| will, of course, rotate with it and there will be'a corresponding reduction in the rate of advancement of the wedge 28 and the cutters I5. If the resistance to advancement encountered by the cutters is great enough so that it overcomes the friction between the faces 51 and 58, then the entire drive unit assembly with the exception of the dogs 6| and the ring 59 will rotate with the housing and there will be no ad- Y vancement of the cutters whatever.

, the threads 46 and 41, so that the advancement is controlled by the resistance encountered and there is, therefore, a differential pressure always tending toadvance the cutters and in many'instances conditions will be encountered wherein the rate of advancement of the cutters will be very slow as compared with the rate of rotation. A very fine adjustment can be accomplished with this type of structure andthe advancement of the cutters may be either uniform in direct proportion to the rotation or uniform as a function of the resistance encountered, or they may be subjected to no advancement whatever, entirely dependent upon the conditions under which `the cutis being effected.

It has been found in actual practice that cutters driven in this manner are exceptionally satisfactory and breakage of the cutters has been practically eliminated. On the other hand a satisfactory cut can be negotiatedbecause it` is only accomplished by `virtue of a differentialpres# sure which is resiliently applied so that it will yield to pressure and avoid undue stresses being applied to the cutters.

In some instances the fish 2 or pipe being cut is not provided with couplings 3 under which the dogs 6l may be anchored and Fig. 4 of the drawing shows a somewhat modified form of pipe engaging portion of the tool which can be employed when` this flush joint pipe is being cut.

The pipe to be out is illustrated at 88 and the flush joint at 8|. The housing 8, slip joint head 56, the shoulder 66, and the antifriction bearing 65 are all identically the same as shown in Fig. l.

The bushing 58, however has been modified somewhat and is shown at 82 as having a tapered seat 83 thereon. This seat is arranged to receive three segments 84 which Yare loosely formed together by a toggle plate 85. This plate is held in position by small screws 86 so that the three sections 84 have limited relative vertical and lateral movement with respect to each other so that they can accommodate themselves to the tapered seat 83. Each of these segments is formed with an inside beveled face 88 which is arranged to carry a jaw 89. This jaw is held in position for limited sliding movement by means of the pin 90 which is movable in a slot 90 in the segment. The lower ends of the jaws are protected by an outstanding shoulder 9| and the upper ends are protected by a similar shoulder 92.

The housing 8 carries one or more inwardly projecting pins 94 which are received in a J-slot 95. The short leg 9E of this slot ordinarily receives the pin 94 when the device is being lowered into the hole because this holds the pipe engaging assembly upwardly so that the segments are not forced toward the center by the beveled face 83. When the elevation where the pipe is to be engaged has been reached the operating string of pipe 'l is rotated sharply a portion of a revolution so that the pin 94 is jerked out of the leg 96 of the J-slot and will move over. to the long leg 9'! so that the slip assembly will drop downwardly relative to the housing 8. In this manner the segments are forced inwardly by the beveled slip 83 and slight upward pull on the entire tool causes the jaws 89 to grip the pipe. So long as the strain is lmaintained on the operating string the tool is anchored in position.

This jaw assembly serves the same purpose as the anchoring dogs 6I in order to provide a resistance to rotation for the slip joint friction drive.

What is claimed as new is:

1. An outside pipe cutting tool comprising a housing, cutter blades therein, means to advance said cutters, a drive thread connection between said housing and said means to effect longitudinal movement upon relative rotation, pipe engaging members tending to restrain said means against rotation, and a slip joint drive between said members and said means whereby the resistance encountered by said cutters if less than the friction drive of said slip joint will effect advancement of the cutter and if greater than such friction will cause slipping of said joint.

2. A differential drive outside pipe cutter including a rotatable set of cutters, a stationary drive unit therefor adapted to engage the outside periphery of the pipe to be cut, a friction drive in said unit, and a friction drive connection between said unit and said cutters, said two friction drives being arranged so that when a predeter- -mined resistance to rotation is encountered by said cutters said first mentioned friction drive will slip and cause said friction connection to be ineffective.

3. VIn an outside pipe cutting tool, means to engage the pipe being cut to' anchor said tool, a slip joint friction drive abutting said anchor, a threaded connection between said drive and said tool, cutter members movable with said tool, and wedge means connected to said drive to advance said cutter members, said threaded connection being controlled to advance said wedge only when the resistance to advancement is less than the friction of said slip joint drive.

4. In an outside pipe cutting tool, means to engage the pipe being cut to anchor said tool, a slip joint friction drive abutting said anchor,athread ed connection between said drive and saidtool,cut ter members movable with said tool, and wedge means connected' to said drive to advance said cutter members, said threaded connection being controlled to advance said Wedge only when the resistance to advancement is less than the'friction of said slip joint drive, and additional means to vary the friction of said slip joint drive.

5. In an outside pipe cutting tool having an anchor and cutters, a pair of friction driving connections located outside of the pipe to be cut and adapted to advance the cutters to working position, and means to transmit the thrust of said cutters to said connections so that the cutters are advanced only when the resistance to advancement is less than the friction of one of said connections. Y

6. In a pipe cutting tool having an anchor and cutters, a drive unit to advance the cutters, a

slip joint connecting said unit to said anchor, means to vary the frictional drive of said joint,

a threaded connection between said unit and said tool to move said unit to advance said cutters, said threaded connection being operative to advance said cutters only when said slip joint exerts a friction in excess of that imparted to the cutters by said threaded connection.

'7. In a pipe cutting tool having an anchor and cutters, a rotatable housing, a drive unit threaded thereto to advance the cutters by screwing of said threads, and a friction connection between said anchor and unit to control the screwing of said threads, as a function of the resistance encountered by said cutters.

8. In a pipe cutting tool having an anchor and cutters, a rotatable housing, a drive unit threaded thereto to advance the cutters by screwing of said threads, and a friction connection between said anchor and unit to control the screwing of said threads by the differential pressure between said friction connectionA and the resistance encountered by the cutters.

9. In a pipe cutting tool having an anchor and cutters,a drive unit having a friction connection normally held stationary by said anchor, and a friction connection having a threaded portion, a threaded member cooperating with said threaded connection to advance said cutters, the threads of said threaded members cooperating to provide a friction connection between said cutters and unit to advance the cutters as a function of the differential pressure between said first friction connection and the resistance against said threaded means by said cutters.

10. In a pipe cutting tool having an anchor and cutters, a drive unit having a friction connection normally held stationary by said anchor, and a friction connection having a threaded portion, a threaded member cooperating with said threaded connection to advance said cutters, the threads of said threaded members cooperating to provide a friction connection between said cutters and unit to advance the cutters as a function of the differential pressure between said first friction connection and the resistance against said threaded means by said cutters whereby shocks or excessive loads may be transferred from said cutters to said first friction connection.

11. In a pipe cutting tool having an anchor and cutters, a body, a bushing mounted thereon, said anchor including pipe engaging slips mounted on said bushing, a ring having a friction surface secured to said bushing, and means operatively connected to said cutters and frictionally engaging said surface to provide a friction connection between the anchor and cutters.

12. In a pipe cutting tool having an anchor and cutters, a body, a bushing rotatably mounted thereon, said anchor including pipe engaging slips mounted on said bushing, a ring having a friction surface secured to said bushing, and means operatively connected to said cutters and frictionally engaging said surface to provide a friction connection between the anchor and cutters.

13. In a pipe cutting tool, a body, cutter members mounted in said body, a bearing surface on said body, al bushing mounted thereon, pipe engaging slips mounted on said bushing, and a ring having a friction surface mounted on said bushing, .and means operatively connected to said cutters and frictionally engagingsaid surface to provide a friction connection between the anchor and cutters.

14. In a pipe cutting tool having an anchor and cutters, a body, a bushing rotatably mounted thereon, said anchor including pipe engaging slips mounted on said bushing, a drive sleeve threaded to said body to advance the cutters by relative rotation of the sleeve and body, and a friction connection between said sleeveand said bushing.

15. In an outside pipe cutting tool, a body, cutters in said body, a bushing having a tapered seat rotatably mounted in said body above said cutters, jaw carrying means slidably mounted within said bushing and adapted to move inwardly upon said tapered seat, and means for releasably holding said jaw carrying means from inward movement.

16. In an outside pipe cutting tool, a body, cutters movably mounted in said body, a bushing having a tapered seat rotatably mounted on the body, jaw carrying means slidably mounted within said bushing and adapted to move inwardly upon said tapered seat and means on said body forvengaging said bushing to hold said jaw means from anchoring position and releasable by rotation of said body to allow anchoring of the tool by said jaw means.

- DEM'PSON H. REED. 

